Accumulators



July 8, 1969 c, wo 3,454,050

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Patented July 8, 1969 U.S. Cl. 138-31 7 Claims ABSTRACT OF THE DISCLOSURE An accumulator for high pressure operation in which the floating piston has an auxiliary guide whereby 1t and its cylinder can be of reduced dimensions and of llghter weight.

Background of the invention Field of the inventin.This invention relates to accumulators of the type which include a cylinder with a free piston therein, one end of the cylinder being precharged under pressure, and the other end providing a resilient receiver.

Description of the prior art.It has heretofore been proposed to provide an accumulator having a hollow circular cylindrical wall with closures at opposite ends and with a free piston interposed between the ends. Such a piston customarily has a length approximately equal to the internal diameter of the cylinder to provide support for its longitudinal axial movement. This length is .provided to prevent tilting which tends to occur when the piston is subjected to pressure. The length required for the piston, influences the length of the cylinder. Even if the piston is made hollow to reduce its weight, the weight of the cylinder, determined by its length, cannot be re duced. There are accordingly serious practical limitations on the reductions in size and weight which can be effected.

Summary of the invention It is the principal object of the present invention to provide an accumulator for pressure fluid which is simple in construction, can be made smaller and lighter in weight than accumulators heretofore available, and which will have a wide range of usefulness.

It is af urther object of the present invention to provide an accumulator for pressure fluid which can be constructed for high pressure operation while having adequate strength and freedom from likelihood of operating difliculties.

Other objects and advantageous features of the invention will be apparent from the description and claims.

Brief description 07 the drawing The nature and characteristic features of the invention will be more readily understood from the following de scription taken in connection with the accompanying drawings forming part thereof, in which:

FIGURE 1 is a longitudinal central sectional view of one form of accumulator in accordance with the invention;

FIG. 2 is a transverse sectional view taken approximately on the line 22 of FIG. 1;

FIG. 3 is a longitudinal central sectional view of another form of accumulator in accordance with the invention; and

FIG. 4 is a transverse sectional view taken approximately on the line 33 of FIG. 4.

It should, of course, be understood that the description and drawings herein are illustrated merely, and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the several views.

Description of the preferred embodiments Referring now more particularly to FIGS. 1 and 2 of the drawings, in which one preferred embodiment of the invention is illustrated, the accumulator there shown includes a cylinder 10 having a hollow circular cylindrical wall 11 of suitable thickness to accommodate the desired internal pressures.

The cylinder 10 has heads or end closures 12 which may have peripheral grooves 13 for the reception of suitable packings 14, such as O-rings. The end closures 12 can be retained against outward movement by peripherally split retainer rings 15 which engage in grooves 16 in the wall 11.

One of the end closures 12 can be provided with a fluid connection 17, connected through a shut ofl valve 18 to a source (not shown) of charging gaseous fluid under pressure. The other end closure 12 can then be provided with a fluid connection 20 for the fluid to be delivered to and from the accumulator.

In many of the accumulators heretofore available, the piston interposed between the end closures 12 would have had a longitudinal axial dimension coresponding to the internal diameter of the cylinder wall 11.

In accordance with the present invention auxiliary support is provided for the piston 22 and the piston 22 which is employed as a movable separator in the cylinder 10 is carried on a supporting rod 23. The rod 23 is mounted at its ends in openings 24 in the end closures 12. The rod 23 can have a diameter of the order of one eighth of the internal diameter of the cylinder wall 11 and preferably has a polished surface.

The piston 23 is slidably mounted on the rod 23 and can have a groove 26 within which a packing 27, such as an O-ring, is carried, to prevent fluid leakage at this location.

The periphery of the piston 23 has a groove 28 within which a packing 29, such as an O-ring, is carried, to prevent fluid leakage at this location. By employing the rod 23 as an auxiliary support for the piston 22, the piston 22 can be of a greatly reduced length or thickness while still being free from tilting within the cylinder 10 upon the application of pressure thereon. The reduction of thickness of the piston 22 permits of shortening the cylinder 10 while retaining the same effective internal volume as with a longer piston.

Referring now more particularly to FIGS. 3 and 4 of the drawings, in which another preferred embodiment of the invention is illustrated, a cylinder 30 is provided having a hollow circular cylindrical wall 31 and a hemispherical end closure wall 32 of suitable thickness to accomodate the desired internal pressures. The use of the hemispherical shape of the end closure wall 32 permits of lesser thickness than that required for the wall 31.

The cylindrical wall 31 has an end closure 33 which may have a peripheral groove 34 for the reception of a suitable packing 35, such as an O-ring, to prevent fluid leakage at this location.

The end closure 33 can be retained against outward movement by a peripherally split ring 36 which engages in a groove 37 in the wall 31.

The end closure 33 can be of any desired shape but is preferably dished inwardly with an internal boss 40.

The end wall 32 preferably has an outwardly extending boss 41 for a fluid connection 42 which is connected through a shut off valve 43 to a source (not shown) of charging pressure.

The end closure 33 has a fluid connection 44 for the fluid to be delivered to and from the accumulator.

A piston 46 is provided within the cylinder 30 and is slidably carried on a fixed supporting rod 48. The rod 48 is mounted at one end in an opening 49 in the wall 32 and preferably has an interior passageway 50 to provide communication between the fluid connection 42 and the interior of the cylinder 30.

The rod 48 at its opposite end is mounted in an opening 52 in the end closure 33. A spring 53 engaged against a shoulder 54 and bearing on the end of the rod 48 may be employed to retain the rod in position.

The rod 48 is provided with an interior pasageway 55 to provide communication between the fluid connection 44 and the interior of the cylinder 30.

The piston 46 can be of any desired shape but is preferably inwardly dished with a central boss 56 slidable on the rod 48 and with a groove 57 for the reception of a packing 58, such as an O-ring, to prevent fluid leakage. The periphery of the piston 46 is also preferably provided with a groove 59 for the reception of a packing 60, such as an O-ring.

The accumulator of the present invention is suitable in a specific embodiment for minimum bursting pressures of the order of 40,000 p.s.i., with a working pressure of the order of 10,000 p.s.i. and with a precharge or loading pressure introduced through the fluid connection 17 or 42 into the interior of the cylinder or 30.

Dry nitrogen is advantageously used as the charging fluid for a particular use. A wide range of operating temperatures can be employed say from 65 F. to 180 F.

As pressure fluid is applied in use, through the fluid connection 20 or the fluid connection 42 the piston 22 or 46 will be moved to a position to maintain equal pressures on opposite sides thereof. The cycling action may be rapid dependent upon the specific conditions encountered in use.

I claim:

1. An accumulator comprising:

a cylinder having closed ends,

a piston in said cylinder movable intermediate said ends,

a support for said piston comprising a rod engaged with at least one of said ends and on which said piston is slidably mounted,

a charging fluid connection at one of said ends, and a working fluid connection at the other of said ends,

said ends having openings for the reception of opposite ends of said rod, and

said rod having a resilient member disposed in one of said openings in engagement therewith and urging it into engagement in the other of said openings.

2. An accumulator as defined in claim 1 in which:

the thickness of said piston along the longitudinal axis of the cylinder is less than the diameter of the cylinder 3. An accumulator as defined in claim 1 in which:

said rod has fluid passageways communicating with on posite interior portions of said cylinder and with which said fluid connections are in communication.

4. An accumulator as defined in claim 1 in which:

said cylinder has a cylindrical wall portion,

said cylinder ends are of dished shape,

said piston is of dished shape,

said support is carried at its ends in said cylinder ends,

and

said rod has fluid passageways communicating with interior portions of said cylinder at opposite ends of said cylinder and with which said fluid connections are in communication.

5. An accumulator as defined in claim 1 in which:

said cylinder has a cylindrical wall portion, and

at least one of said cylinder ends is of dished shape and is integral with the cylindrical wall portion.

6. An accumulator as defined in claim 5 in which:

the other of said cylinder ends is removably mounted in the cylindrical wall and is of dished shape.

7. An accumulator as defined in claim 5 in which:

said piston is of dished shape.

References Cited UNITED STATES PATENTS 2,729,244 1/1956 .Alaska et a1. 138-31 2,800,924 7/1957 Antrim 13831 3,043,340 7/1922 Rehbock 1383 1 3,122,169 2/1964 Kendall 138 31 3,158,180 11/1964 Greer 13831 HERBERT F. ROSS, Primary Etraminer. 

